Examine source code of Duolingo Boost

{
  "author": "Richard \"Richdark\" Filipčík",
  "background": {
    "scripts": [
      "scripts/dev.js",
      "scripts/common.js",
      "scripts/jquery-3.1.1.min.js",
      "scripts/background.js"
    ]
  },
  "browser_action": {
    "browser_style": false,
    "default_icon": "icons/logo-48.png",
    "default_popup": "html/popup_login.html",
    "default_title": "Duolingo Boost"
  },
  "content_scripts": [
    {
      "css": [
        "styles/duolingo.css"
      ],
      "js": [
        "scripts/dev.js",
        "scripts/jquery-3.1.1.min.js",
        "scripts/print.min.js",
        "scripts/common.js",
        "scripts/duolingo.js"
      ],
      "matches": [
        "*://www.duolingo.com/*",
        "*://www.duolingo.cn/*"
      ]
    }
  ],
  "description": "Duolingo Boost enhances Duolingo website for even better language learning experience.",
  "icons": {
    "16": "icons/logo-16.png",
    "32": "icons/logo-32.png",
    "48": "icons/logo-48.png"
  },
  "manifest_version": 2,
  "name": "Duolingo Boost",
  "options_ui": {
    "page": "html/options.html"
  },
  "permissions": [
    "*://www.duolingo.com/*",
    "*://www.duolingo.cn/*",
    "contextMenus",
    "cookies",
    "notifications",
    "storage",
    "tabs",
    "webRequest",
    "webRequestBlocking"
  ],
  "version": "0.4.1"
}